Automatic control for trolley frogs



1942- E. C.'BROWN 2,268,922

AUTOMATIC CONTROL FOR TROLLEY'FROGS v I Filed Oct. 7', 1937 1 2 Sheets-Sheet l INVENTOR EVERETT C.- BQOWN ATTORNEY Jan. 6, 1942. E. c.v BROWN AUTOMATIC CONTROLFOR TROLLEY'FROGS Filed Oct. 7, 1937 2 Sheets-Sheet 2 INVENTOR EVERETT c. BROWN ATTORNEY *Iii Patented Jan. 6, 1942 AUTOMATIC CONTROL FOR TROL JEY -FR0GS j Everett 0. Brown, Louisville, Ky., assignor to Cheatham Electric Switching Device Co.,"In-

corporated, Louisville, Ky., a corporation of V Kentucky Bm Q i nOctoherL'I,1937, SetialNo. 167,687

11 Glaims. 1191-38) My invention relates toanfi-mproved control system for automatically operating ,el ectricallyoperated trolleyfrogs-at a turn-out? on a trolley bus system. 7

m-trolley bus systems'where a turn-,out is l e i for the turno 1 1 troute, a similar set of contact ld vices longitudinally oilset with'respect to required, it is necessary to .provide a switching device to direct the path of travel of the trolley bus wcurr-ent collectors along the overhead conductors. 4 a l In trolleytbus operation, experience has-shown that theidrag of the trolley poles cannotlbe depended upon to di-rect' the current collectors through trolley frogs at a turn-out point properly, as is the case in electric street railway operation, where the rails and switch tongue -pro- Z,

contactdevicein one conductor is engaged and disengaged before the contact device in the other c n u r -e e d th r fq e Pre i ie ra i n fi e Imetoneue Thus, to provide operation of'the irog tongues each othera provid d and er ei sedjsot l they are simultaneously engaged, onlyfwhen the vide a definite path, of travel for the streetcars.

is, to provideoselective ,operation of the electrically-operated I tongues, the operator -is required to place the bus motor controller in ,either the .on or off position, .dependingonwhich current colleotorsassun e the said angularlongitudinal-p s e Various modifications of, the foregoing have been tried, but each are defective in that any angularityof the bus intermediate the mentioned positions, for. the ,through and "fturn-out movements, reduces materially the length of time the current collectors simultaneously ena -t e i t ct er e I nso'me instances, suitable markings havebeen placed on the surface of the street paving to indicate to the bu s operatorthe approximate path the bus must follow to provide proper selection and operation ot the trolley frog tongues.

Thuslalt'hough the systemutilizing "the longitudinal displ acement of the current collectors to provide selection has been recognized as desirable over the former power-on? and power-off arroute the bus is to .follow. Usually, in ,this

method of ,,control, the mechanism is arranged a vide selective operation of the electrically-oper- .atedtongues according to thessimultaneous zengagement of contact devices located adjacent :the

overhead-conductors. I

Thus, a bus following the through route,

will provide little or .ndangular longitudinal displacement of the current-collectors with respect to theoverhead conductors, and, upon simultaneouslyengaginga pair of contact devices 10- catedsubstantially opposite each other,-a mechanism ,is operated to positionr-the frog tongues to ,accommodate the through movement.

o viously, when the bus is following the turn-out route, a2. substantial, "angular longitudinal ==dis- -placement of the current collectors with respect v,to the overhead conductor-sis provided,;and-the rangement the embodiments of the principle thus far have inherent disadvantages.

It is thereforetheobject of my invention to eliminate these inherent disadvantages, and to providera system that Will provide a decided improvement inthe performance of the said displacement methodof selection.

A further object of my invention is to provide a system that will require on'ly'the -minimum number of contact devices.

Another object of my invention is-to provide quick-acting relay apparatus arranged-and constructed so that 'the selection willbesubstantially instantaneous upon the engagement of thecurrent collectors and contact devices, and ;-which will retain such-selection regardless of-lany changes that 'maytake place in the relative angularity of the bus thereafter. 1

A further object- 'of my invention-is -.to provide relay, apparatus -that will establish a predeter- "A still "further object of ,my invention resides in organizing the relay apparatus so that one contact device:- always tunctions to provide selecti nvwhiletheother contactdev-ice alwaysiunctions to provide operatiomaccording to the selection determined by the said one contact device.

These and other objects of my invention, as may hereinafter appear, are best understood from the following description of the accompanying drawings illustrating various embodiments thereof.

In the drawings:

Fig. 1 is one illustration of a control system for an electrically-operated trolley frog embodying the principal features of my invention;

Fig, 2 illustrates one modification of Figure 1, in which the connections to relay X and the trolley-frog operating coils are altered, so that the operating circuit of said coils is entirely independent of the contact devices;

Fig. 3 illustrates a modification of Figure 2, introducing a time-element control to provide a definite time of operation for the trolleyfrog operating coils;

Fig. 4 illustrates one modification of Figure 3, to obviate the use of the mechanical latch La employed in Figures 1, 2 and 3.

Referring now in particular to Figure 1, it will be observed that the system includes a pair of overhead current conductors P and N. These conductors are engaged by the current collectors of the trolley buses, and supply the feed and return circuits, respectively, for the propulsion current of the trolley buses. The characters F and G, designate movable frog tongues at a turn-out point, which provide a definite path of travel for the collectors of the trolley buses to either the through or turn-out routes. The characters PS and NS designate the conductors for the through route, while characters PC and NC designate the conductors for the turn-ou route.

Pairs of operating coils CISI and CS, are provided to operate electrically frog tongues F and G respectively.

Located adjacent the conductors P and N are positioned contact devices I and 2. The character O designates a slight displacement in the longitudinal positioning of the contact devices, sufficient to assure operation of relay Y in advance of relay X, for the bus following the through movement.

Characters J and K designate the current collectors of a trolley bus preparing to follow the turn-out route to the right. Therefore. the left-hand collector J is in advance of the righthand collector K. The character Q designates the lon itudinal displacement between the current collector J and K when the trolley bus is pre aring to follow the turn-out route.

Characters L and M designate the current collectors of a trollev bus preparing to follow the through route. Therefore, the collectors are substantially opposite each other.

To differentiate between the collectors of the vehicle following the turn-out route, and those of the vehicle following the through route. the former are shown in solid lines, while the latter are shown in dotted lines.

Describing first the operation of the apparatus in Figure 1 for collectors J and K, it will be obvious that, whenever the longitudinal distance Q is greater than the longitudinal distance 0. the collector J will engage contact device I before collector K engages contact device 2. Thus relay X is operated before relay Y.

The circuit providing energization of the oper ating coil of relay X being completed from positive conductor P, through collector J, contact device I, wire 5, coil of relay X, wire 4, resistor R, wire 3 to negative conductor N.

The operation of relay X raises armature 8, actuates mechanical latch La, and thereby locks armature III in engagement with back contact I I. Raising armature 8 also brings same into engagement with front contact I, thereby providing energization of operating coils C and CI. The circuit for the latter being completed from positive conductor P, through collector J, contact device I, wire 5, wire 6, front contact 1, armature 8, wire 9, armature I0, back contact II, wire I2, operating coil C, wire I3, operating coil CI, Wires I4 and 22 to negative conductor N. Energizing operating coils C and CI, operates frog tongues F and G, respectively, thereby forming a definite path of travel for collectors K and J to the turn-out route.

A short time after collector J engages contact device I, collector K engages contact device 2. The engagement of collector K and contact device 2 provides energization of the operating coil of relay Y. The latter circuit being completed from negative conductor N, through collector K, contact device 2, wire I9, resistor RI, wire 20, coil of relay Y, wire 2| to positive conductor P.

It will be obvious that the energization of the coil of relay Y at this time cannot raise armature ID, as latch La is retaining same in engagement with back contact II, as aforesaid.

Collector J ordinarily disengages contact device I before collector K disengages contact device 2.

When collector J disengages contact device I, the circuit providing the energization of the coil of relay X via wire 5, and likewise the operating coils C and CI via contact I, is opened. Thus, armature 8 returns to normal unattracted posi tion and removes latch La from armature I0. However, since the circuit via contact I is open, no further operation of the trolley frog coils takes place at this time.

Subsequently collector K disengages contact device 2, thereby do-energizing the coil of relay Y, which restores armature III to normal unattracted position.

Obviously, since the sequence of disengagement of collectors J and K is not material to the operation of my invention, they can be made of any length, consistent with operating requirements, so long as the longitudinal distance 0 is provided, as aforesaid.

Describing now the operation of Figure 1 for collectors L and M, it will be obvious that, whenever the longitudinal distance Q is less than the longitudinal distance 0, or when the collectors L and M are substantially opposite each other, the collector M will engage contact device 2 before collector L engages contact device I. Thus relay Y is operated before relay X, and armature I0 is raised into engagement with front contact I5. The subsequent operation of relay X, actuates latch La to lock armature I 0 in engagement with contact I5, and raises armature 8 into engagement with front contact I.

Since armature III is in engagement with front contact I5, the engagement of armature 8 and front contact I provides energization of the operating coils S and SI. The circuit for the latter being completed from the positive conductor P, through collector L, contact device I, wire 5, wire 6, contact 1, armature 8, wire 9, armature I0, contact I5, wire I 6, operating coil S, wire II,

operating coil SI, wires I8 and 22 to negative conductorN. Energizing operating coils S and'flSl operates "frog tongues F and -respectively, thereby forming a definite path' oftravel 1 for the collectors L and' M to the throu'gWroute.

Ordinarily collectorfM- disengages contact device 2 bforecollector 'Ldisengages contact device I. "When collector M disengages-contact device '2, the Ci1 of "relay Y" is deenergized. I-Iowever, armature can not-disengage front contact 15, 'as' latch -La retains the engagement thereof as long as armature 8 is raised and engaging contact! Therefore, when collector L -disengages-con- 'tactdevice {I ,--the circuit providing the energizati'on of the coil*of-.relayX =via wire 5, and likewise the operating coils S and S I via contact "I, is opened. Thus, armature 8-returns to normal unattracted position and removes latch La" from armature"), which, in turn, permits-armature "Ill to'return to normal unattracted position.

Each of the trolley frog-tongues F and G are provided with a toggle spring, orits equivalent, toretain samein'either of their positions. Since this feature does not form apart of-thisinvention, and-since the construction and'arrangement of such is well'known in thear't, ithas not been illustrated in the accompanying drawings.

From the. foregoingpit willbe further obvious .that, since relay Y'must 'opera'tebefore relay X to provide the proper operation of the "frog tongues F and G for the through movement, the relay "Y-can be constructed and-arranged to be faster acting than relay X, therebyobvia'ting therequirement of the longitudinal distance '0 betw'eencontact devices-I and 2. Under'this'arrangement the contact devices-l and"! are located substantially opposite each other. It is to be understood, however, that'in-providing for such an arrangement, :the-speedof'relayX must .be arranged to operate during the *time .determined-by the longitudinal distance Q.

:Thus, although I have illustrated. a longitudinal distance i .0 between contact devices and 2 as a "preferred manner LOT providing an :opera-' tion of 1 relay :Y before relay'iX, 11 :do not "desire to be limited to this iarrangement-other'than by the scopeof the appended clainis.

- -The cpera'tion -of therapparatus in Figure 2ais substantially the'same as that of Figure 1. However, inFigure'Z, the circuits of the trolley'frog operating coils havebeenaltered-so 'as'to be entirelyindependent of the'contact device I. Thus, it :is considered suflicient rmerely to "designate these alterations, and "the :features provided thereby. Comparing Figure i 2iwith Figure 11, it

completed from positive conductor 'P, through collector J, contact *device 1, wire 3, resistor -R,

-wire"4,"coil of relay X, rwir -e5'ito negative conductor. N.

" The operation ofrelaylX raisesaarmature 8, ac-

'tuates mechanical latch La and thereby locks armature l 0 vin engagement'withxback contact I l Raising "armature '8 :also brings'same into en- The contact'larmature 8, wire 9,-armatu-re l0, back contact 4 I., wire* l'2,-.operating coil C,-wire t3, op-

..erating coil C|,':'Wlle l'8, to positive conductor. P. vThus,-the-ienergization of the operating coils C and- C-l has been' provided for, without'requiring the current therefore to-flow throughwthe con- .tact'device'l yand currentacollector J, as described r'forFigure l.

The advantagesof this arrangement will be more'apparent :-when* the following description in connection with Figure3 is read. i

. In Figure 3, theelectrical connections of the trolley-frog-operating coils CS and C|Sl are substantially thesame, as illustrated and describedfor Figure 2, except that an armature. 24,

. through the .trolleyfrog operating coils S and will beobservedwthat wires =3land "5 of :Figurez have been connected reversely: to that illustrated and described forFiguregl.

Thus, wire 3 being connected ;to conta'ctflde- -vice.l, and wire :5 .tQ negative conductor 5, .pro-:

vides -a -direct-electrical-connection of *armature'ifl to the negative conductor iN whenever the armature raised intoengagement with front con- .tact 1. Therefore, to provide the proper completion of the circuits for :-the 'ztrolley-zfrog oper- .the altered circuit connections of the .trolley frog operating coils in Figure 2, it will :be assumed I that the collectors J and'Klapproach:the"turnout.

When collector J :engagescontactdevice"I, re-

lay. X will operate, the; :circ.uit .thereforebeing In thisrespect attentionis directed to the fact that ordinarily the trolley frog operating coils CS-and Cl-SI have a very low resistance in comparison. with the resistance of the coil of relay Y .and the resistorRl. Thus, the current flowing through the coil of relay Y and resistor RI, .doesnot energize the trolley-frog coils S and ..SI .sufiicientflto operate their respective frog tongues Fahd G.

-In-Figure 3, the armature -24 of :the time-element relay T, is substantiall-yihstantly raised, when the coil of relay T is energized, but is de- .la-yed in its ,release whenythe-coil'of relay T is de-energized. This action ofrelay Tissymbolicallysrepresented by conventional symbols'employed inFigure 3.

Referring-more indetail to Figure 3, it will be observedthat the coil of-relay T is'normally energized, thereby retaining-armature 24 in engagement with front contact 25. The circuit of the operating coil .of-.relay T being completed from the negative conductor N, through wire 5, wire 6,

,coil of relay T, wire 26, resistor R2, back contact 21, armature 8, :wire 9, armature |0,'back contact-J I, wireY-ILoperatingcoiI C, wire I3,-operating coil-CLwire :14, topositive conductor P. The

i resistance of thetrolley-frog operating coils CS and.C|SI,are also Very :low in resistance in comparison with that'of'resistorRl and the coil of relay T. Thus, the current flowing through the coil of relay T and resistor RI is not sufficient tooperativelyxenergize the'trolley-frog coils Cand Cl. 1

fIt-is tome. observed "that the circuit-for the coil ofzrelay Tiis completed through back contact 21 and armature 8 of relay X. Therefore, whenever .sarmature s38 Lis raised to directcurrent-to the trolley-frog operating coils, the operating coil of relay'Tzis'de-energized.

For the purpose of illustration, it willgb'e as- :'sumed that the collectors J and Kwapproach the turn-out. -When the collector J engages contact device I, the pick-up coil of relay X is energized, as described in connection with Figure 2, thereby raising armature 8 and actuating latch La to lock armature I in engagement with back contact I I. Raising armature 8 de-energizes the coil of relay T, as aforesaid. However, armature 24, is delayed in its release and retains engagement with front contact 25 for a predetermined time thereafter. Raising armature 8 also brings the armature into engagement with front contact I, and completes the circuit of operating coils C and CI as follows: from negative conductor N, through wire 5, wire 6, front contact 25, armature 24, wire 23, low resistance holding coil H, contact I, armature 8, wire 9, armature l0, back contact I I, wire l2, operating coil C, wire [3, operating coil CI, wire [4 to positive conductor P.

The current flowing through the low resistance holding coil H is sufiicient to retain armature 8 raised, and to energize the trolley-frog coils suincient to operate their corresponding frog tongues F and G. Thus, even though the collector J may immediately thereafter disengage contact device I, as would be the case under relatively high speeds, the armature 8 is retained raised as long as operating current flows to the trolley-frog operating coils.

Assuming collector J has disengaged contact device I, then a predetermined time after the raising of armature 8, armature 24 releases and removes operating current from trolley-frog coils C and Cl Removing operating current from the trolley-frog coils de-energizes holding coil H, thereby releasing armature 8. Armature 8 releasing, reconnects back contact 2'! and energizes the operating coil of relay T, which, in turn, raises armature 24 to its normally attracted position.

It is believed that further operation of Figure 3 will be obvious, when the selective operation of relays X and Y is considered in terms of the description of Figures 1 and 2. Therefore, further description of Figure 3 is omitted.

Thus, in Figure 3, I have provided automatic means for determining the length of time the trolley-frog operating coils shall be energized, and means that will provide a definite time of current application to the trolley-frog coils, for the operation of frog tongues F and G, inde pendently of the time the contact device I is electrically connected to the positive conductor P.

Concerning the operation of relay T, emphasis is now made of the fact that the time of release of armature 24 is made sufiiciently long to retain operating current flowing to the trolley frog coils, under ordinary operation, until the current col-- lectors have passed entirely over the frog tongues F. and G. Thus, the prolonged energization of the trolley-frog operating coils serves to retain the operation of the frog tongues, and thereby prevent accidental changes in the operation thereof because of excessive overhead vibration, etc.

In Figure 4 the apparatus of Figure 3 is illustrated in modified form in such a manner as to obviate the use of the mechanical latch La, but yet to retain its functions. Thus, the modification, shown in Figure 4, illustrates an entirely electrical method of retaining armature III in either of its positions.

To provide for this change of construction, the mechanical latch La and its associated parts have been omitted. In Figure 4, wire 2| is connected to wire 9 instead of wire [5, as shown in Figure 3. Thus, under this system of connections, wire 9 is substantially at negative potential whenever operating current is flowing from contact I to the trolley-frog operating coils, and since contact device 2 is connected to negative potential through collectors K or M, coil Y is substantially tie-energized at such times. Therefore, if armature 8 is raised while armature I0 is engaging back contact i l, the placing of wire 9 at negative potential prevents an energization of the pickup coil of relay Y, when contact device 2 is subsequently engaged by collector K.

To provide for the retaining of armature ill in engagement with its front contact IS, a low resistance holding coil III is provided and placed in series with the "through route trolley-frog operating coils S and SI.

Therefore, if armature 8 is raised while armature I0 is engaging front contact IS, the placing of wire 9 at negative potential de-energizes the pickup coil of relay Y. However, as long as operating current flows through armature l0 and front contact I5 to the operating coils S and SI, the holding coil HI is retained energized suflicient to hold armature II) in the raised position.

Since the operation of Figure 4 is otherwise identical to Figure 3, further description is considered unnecessary in view of the specific treatment of the constructions leading up to the development of Fig. 4.

Thus, in Figure 4 I have illustrated an entirely electrical method of retaining the selective operation of armature l0. Therefore, although I have illustrated a mechanical means in connection with Figures 1, 2 and 3, I do desire to be limited to either specific embodiment, other than by the scope of the appended claims.

Having thus described my invention, I claim:

1. In a switching system for a pair of current collectors mounted on a vehicle, a pair of main trolley wires of opposite polarity and a branch wire for each main wire, a trolley frog at the intersection of each main and branch wire having a movable tongue for guiding a current collector on the vehicle either along the main wire or on to the branch wire depending on the position of the said movable tongue, means including a pair of operating coils associated with each frog for actuating its tongue in opposite directions, a single contact device located adjacent each main wire on the approach side of each frog so as to be electrically connected to its respective associated trolley wire during the passage of one of said current collectors therealong, and a relay selectively controlled by the engagement of the current collectors on the vehicle with the said contact devices dependent upon whether the current collectors both engage the contact devices at the same time or one in advance of the other and cooperative with one of said contact devices for selectively energizing the operating coils of the frogs, said order of engagement of the current collectors with the contact devices being dependent upon the angular position of the vehicle with respect to the main trolley wires.

2. In a switching system for a pair of current collectors mounted on a vehicle, a pair of main trolley wires of opposite polarity and a branch wire for each main wire, a trolley frog at the intersection of each main and branch wire having a movable tongue for guiding a current collector on the vehicle either along the main wire or on to the branch wire depending on the position of the said movable tongue, electro-magnetic means foi: actuating'the frogs: in opposite. directions; .a single contact device: located adjacent each. main wire onthe approach side of the frog so. as. tobe electrically-connected with. its associated wi r'e during the passage of-one of said currentcollectors therealong, a single relay for selectively'con- I trolling in conjunction with one of said. contact.

devices: the energization ofthe elcctro-magnetic actuating means for the frogs, said relay being selectively, controlled by the engagement of the said current collectors with said contact devices;

whereby the movable tongues are actuated ino-ne predetermined direction when one of said contact devices is engaged by its associated current-c01- lectorbefore the other'contact device is. engaged the main conductors. and. inadvance oft-the entring end offthesaid'frogs, each of.saidv.devices having, a.normally-open switch adapted. to be closedfb yl the: corresponding collector in passing thelsaidi device; a pair of relays, each relay. hav- 11 g" anI operating; coil. and switche operated thereby; anoperating circuit" for the. operating coil-f of one, of the. said relays including thesource oi power and; the normally open; switch of the contact device located adjacent orient the. said conductors ani'operating circuit forthe relay coil oil, thefcthen offsaid. relays including; the source qfil pnwerv and 'the'. normally-open switch. of the contact device located adjacent'ithe other of..,sai'd by; the other current collector and. in theother trolley wires of opposite.polarityranma branch wire for each main wire, a trolleyffrogat -the intersection of. each main and branch wire-havxing a movable tonguefor guiding a -.current;collector on the. vehicle either along the-mainwire oron to the branch wiredepending on the position of the-said movable tongue; means; includeing a: pair; of operating; coils associatedwith each frogfor actuating its tongue in Opposite directions,;a single contact device located adjacent each main wire on the approach side of' the frog so as to be electrically connected to itsrespective associated trolley wire during the passage of. one of said current collectors therealong, an

contact device associatedwith theother-main trolleywire, a relay for selectively controlling said energizing circuit, whereby themovable tongues of the frogs are actuated to their different positionswhenthe saidone contact dee vice is, engaged by its associated current col.- lector dependent upon the position of the-relay; said relay being, selectively controlled bygener gization from both ofsaid contact devices, wherebyrsaid relay functions to control the energizing circuit for theoperatingcoi-ls of the fIOgSf-tO. opcrate the movable tongue members thereof to one position when the said one.contactdevicesisem ga ed by its associated current collector before the otherconta'ct device is engaged by its associatedcurrent collector. and to the other position when said contact devices are engaged by their associated currentcollectors substantially simultaneously.

4. In a switching, system for a pairof current collectors mounted upon a vehicle; a source of power; a pair of main trolley conductors. and. a branch conductor-for each main conductor; a

trolley-frog at theiunction of each. mainand lectively by the selective energization of. the said conductors; an; operating circuit for. one of; said electromagnets including the sourcelof. power; a

nqrmally open switch of thelsaid one relay and alnorrnally -closedswitch of. the said lother relay;

an:operating circuit for. the. othersoffsaidl "electromagnets, including, the... source of power, a normally-openr'switch of the said onereny. and. a normally-open switch of the. said other relay; means,- operably associated. with the. said'. other relay and operating. in response to. an operation of. the said 'onefrelay, for. retaining. the. switches oithe-said otherrelay inoneor. the other. of

their. operablefp ositions the position. of the cur.- rent. collectors relative. one .to the other. longi tudinally of the. main conductors varying, with the angularity of thevehicle relative tothemain conductors, andthe. said. positioning of. the collectorslandthe aforesaid predetermined position otlthevco'ntact devices being suchas 'to determine selectively-the: energization of the'operating coils of;the said relays inaccor'dance with the selective. closing ofthe saidswitches of the contact devicesas. determined by the. angularity of the yehicle. relativeto the main conductors as the collectors pass the said devices, therebyto deterninerselectivelythe 'energization of l the operating circuits of the said electromagnets; and means, operably associated with the actuatingmechanism-for the. said one movable elementfand. the said other movable element, for" correspondingly moving. the said other, movable; element to; its

' corresponding operablepositions.

5.1a a switchingsystemfor a pair of current collectors mounted upon a: vehicle; a pair of main .-trolley-conductorsof opposite polarity 1 and a: branch conductor for each am; conductor; a trolley. frogf; at the. junction of each main and branch conductor, each frog. having a movable elementoperable; either to one or to theother of two positions for guidinga collector. either along: the corresponding main I conductor 7 or from thewsaidn'main conductor onto-the corresponding branch conductor; an actuating mechanism for electromagnets operably-associated therewithijfo'r I 560 .onelof-the saidzmovab-le elements includingtwo moving thesaid.oneselement'either to one onto .the otherof its; operable positions as determined by: the selective energization of the saidzelectroel'ectromagnet's; a contact device located ad-J'acent each mainconductor in a predetermined magnets; 'a contactv device located adjacent each main conductor. in a predetermined positionrela- .tive -one;tothe other longitudinally of the main conductors: and a in advance of. the enteringcend :of thesaid frogs; each of thesaid devices adapted to betelectricallycconnected 'to the corresponding mainlconductor bya collector passingthe said zdevice-;.;. apair of: relays, each relay having an operating coil and switches operated thereby; a control; circuit: for" energizing the operating-coil OfZOIlG of'said relays including an electrical .con- .nectioniirom; one-terminal of: the operating. coil .of-.--the said: onerrelayto the contact device: ad

jacent one of said conductors, and an electrical connection from the other terminal of'the operating coil of the said one relay to the other of said conductors; a control circuit for energizing the operating coil of the other of said relays including an electrical connection from one terminal of the operating coil of the said other relay to the contact device adjacent the said other conductor, and an electrical connection from the other terminal of the Operating coil of the said other relay to the said one conductor; an operating circuit for one of said eleotromagnets including electrical connections to the said conductors, a normally-open switch of the said one relay, and a normally-closed switch of the said other relay; an operating circuit for the other of said electromagnets including electrical connectionsto'the said conductors, a normally-open switch of the said one relay, and a normallyopen switch of the said other relay; a mechanical latch, operably associatedwith the switches of the said other relay and operating in response to an energization of the operating coil of the said one relay, for retaining the switches of the said other relay in one or the other of their operable positions; the position of the current collectors relative one to the other longitudinally of the main conductors varying with the angularity of the vehicle relative to the main conductors, and the said positioning of the collectors and the aforesaid predetermined position of the contact devices being such as to determine sequentially the energization of the operating coil of the said relays in accordance with the sequential connecting of the contact devices to their respective conductors as the collectors pass the said devices, thereby to determine selectively the energization of the said electromagnets; and means, operably associated with the actuating mechanism for the said one i movable element and the said other movable element, for correspondingly moving the said other movable element to its corresponding operable positions.

6. In a switching system for a pair of current collectors mounted upon a vehicle, a pair'of main trolley-conductors of opposite polarity, and a branch conductor for each main conductor; a trolley frog at the junction of each main and branch conductor, each frog having a movable element operable either to one or to the other of two operable positions for guiding a collector either along the corresponding main conductor, or from the main conductor onto the corresponding branch conductor; an actuating mechanism L for one of the said movable elements including two electromagnets operably associated therewith for moving the said one element either to one or to the other of its operable positions; means, operably associated with the actuating mechanism and the other of said movable elements, for correspondingly moving the said other movable element to its corresponding operable positions; a contact device located adjacent each main conductor in a predetermined position relative one to the other longitudinally of the main conductors and in advance of the entering end of the frogs, each of the said devices adapted to be electrically connected to the corresponding main conductor by a collector passing the said device; the position of the collectors relative one to the other longitudinally of the main conductors varying with the angularity of the vehicle relative to the main conductors, and the positioning of the collectors and the aforesaid predetermined position of the contact devices being such as to connect selectively the said contact devices to their respective conductors as determined by the angularity of the vehicle relative to the main conductors as the collectors pass the said devices; a relay having an operating coil and a normally-closed switch opened by the energization of the said coil, and a normally-open switch closed by the energization of the'said coil; a circuit for energizing'the said operating coil including the main conductors and the contact device adjacent one of the said main conductors; an operating circuit for one of the aforesaid electromagnets including the main conductors, the normally-closed switch of the said relay and the contact device adjacent the other of said conductors; an operating circuit for the other of the aforesaid electromagnets including the main conductors, the normally-open switch of the said relay and the contact device adjacent the said other of said conductors; control means, operably associated with the said relay and the contact device adjacent the said other of said conductors, for retaining the switches of the said relay in their said normal positions when the contact device adjacent the said other of said conductors is connected to its respective conductor before the contact device adjacent the said one of said conductors is connected to its respective conductor; and control means, operably associated with the said relay and the contact device adjacent the said other of said conductors, for retaining the switches in the positions efiected by the energization of the operating coil of the said relay when the contact device adjacent the said one of said conductors is connected to its respective conductor before the contact device adjacent the said other of said conductors is connected to its respective conductor, thereby to operate selectively the said actuating mechanism and associate means for moving selectively each of the said movable elements to one or the other of their operable positions.

7. In a switching system for a pair of current collectors mounted upon a vehicle; a pair of main trolley-conductors of opposite polarity, and a branch conductor for each main conductor; a trolley frog at the junction of each main and branch conductor, each frog having a movable element operable either to one or to the other of two operable positions for guiding a collector either along the corresponding main conductor, or from the main conductor onto the corresponding bran-ch conductor; an actuating mechanism for one of the said movable elements including two electromagnets operably associated therewith for moving the said one element either to one or to the other of its operable positions; means operably associated with the said actuating mechanism and the other of said movable elements, for correspondingly moving the said other movable element to its corresponding operable positions; a contact device located adjacent each main conductor in a predetermined position relative one to the other longitudinally of the main conductors and in advance of the entering end of the said frogs, each of the said devices adapted to be actuated by a collector passing the same; the position of the collectors relative one to the other longitudinally of 'the main conductors varying with the angularity of the vehicle relative to the main conductors, and the positioning of the collectors and the aforesaidpredetermined position of the'contact devices being such as to provide selective actuation of thesaidzcontactidevices as determined by'theangularity' or: the vehicle-relative to the main conductors: as the collectors pass the contact devices; afirst'xrelay having selector switches operably associated'with the said electromagnets for selectivelydirecting operating current toone'or the othergof said electromagnets, and having an:operatingrcoil op,-

erably" associated with one of the; saidccontact devices for'operating the said selector switches in\response to an, actuation of thesaid one contact device; a second-relay having a. control switch operably associated with the said selector switches for establishing a flow ofoperating-current to one or the other of said electromagnets in accordance with the, selective operation of the said: selector switches, and having an operating; coil, operably associated with the other of saidcontact devices for operating the said control'switch inresponse to an actuation of thesaidtother contact device; and means operably associated-with the said first relay, and operating in response to an operation of the said second relay, for retaining the selectioniof, the selector switches as long as operating current flows to the said electromagnets.

8. A switching system for currentcollectors of devices a third: relay havingv a delayed-opening switch, operably -associated with the; said electro, magnets' for discontinuing the flow-of operating current thereto, and having an operating; coil operably associated with the said secondrelay for opening the said delayed-opening, switch" a predetermined time after the operation of the saidsecond relay; means operablyassociated\with the said first relay, and operating'in response to an operation of the said second relay, for: retaining-the selection of the said selector switches as longv as operating current flows to the said electromagnets; and means operably associated with the said second relay, and operating in-responseto'an operation of the said-control switch, for retaining the said control switch operated as longas operating current flows to: the, said electromagnets.

9. In a switching-system: for apairof current collectors mounted upon a dirigiblevehicle; a source of power; a pair of main trolley-conductors for the said collectors, and'a branch con- 7 ductor for each main-conductor; .the position of adirigible vehicle, including, in combination, a

pair of main trolley-conductors of, opposite po larity, and a branch conductor for each main conductor; a pair of current collectors mounted upon a-dirigible vehicle and collecting propulsion current from the said conductors, the positions of the collectors relative one to the other longitudinally of the main conductors varying with the angularity of the vehicle relative to the main conductors; a trolley frog at the junction of each main and bran-ch conductor, each frog ,havinga movable element operable either to one or to the other of two operable positions for guiding a collector either along the corresponding main conductor, or from the main conductor onto, the corresponding branch'conductor; an actuating mechanism for one of the said movable elements including two electromagnets operablyassociated therewith for moving the said one. elementeither to one, or to the other of its operable positions; means operably associated with the saidactuating mechanism and the other of said. movable elements, for correspondingly moving the said other movableelement to its correspondingly, op'- erable positions; a contact device located adjacent each main conductor in a predetermined position relativeone to, the other longitudinally of the main conductors and in advance of the entering end of the said frogs, such that the contact devices are actuated selectively by the collectors, as determined by the angularity of the vehicle relative to the main conductors as the collectors pass thesaid contact devices; a first relay having selector switches operably associated with the said electromagnets for selectivelydirecting operating current to one or the other of said electromagnets, and having an operating coil operably associated with one of said contact devices for operating the said selector switches in response to an actuation of the said one device; a second relay having a control switch operably associated with the said selector switches for establishing a flow of operating current to one or the other of said electromagnets in accordance with the operation of the selector switches, and having an operating coil operably associated with the other of said contact devices for operating the said control switch in response to an actuation of the said other of said contact the collectors relative one to the'other longitudinallyof the main conductors varying with the angularity of the vehicle, relative tothe main conductors; aztrolley frog at the junction of each main and branch conductor, each frog having a movable element operable either to one or to the other of. two positions for guiding a collector either along-the corresponding main conductor or fromthe said main conductor onto the corresponding branch conductor; an actuating mechanism for one of the said movable elements including two electromagnets operably associated therewith for moving the said element either to one or to the other of its operable positions; means operably associated with the said mechanism, and with the other of saidmovableelements, for correspondingly moving the said-other movable element to its corresponding operable positions; a contact device, located adjacent each main :conductorin a predetermined position relative one to the other longitudinally of the main r conductors and in advance of the said frogs;'the

said contact devices adapted to be actuated'selectively by the collectors as determined by; the

angularity of the-vehicle relative to the main conductors as the collectors pass the said devices; a normally-open switch, operably associated with each contact device, each switchadapted to be closed by the-actuation of its correspondingdevicega pair of relays, each' relay having an operating coil and-switches operated thereby; an operating circuit for theoperating coil of one of the said relays including the source of 'power and the normally-open switch of the contact device located-adjacent one of thesaid conductors; an operating circuit for the relay coil of the other of said relays including the source of power and the normally-open switch of the contact device located adjacent the other of said conductors; a circuit for energizing one one conductor is actuated before the device adjacent the said other conductor; and means operably associated with the said other relay, and operating in response to an operation of each of the said relays, for retaining the switches of the said other relay in the positions effected by the energization of the operating coil thereof, when the device adjacent the said other conductor is actuated before the contact device adjacent the said one conductor.

10. In a switching system for a pair of current collectors mounted upon a dirigible vehicle; a source of power; a pair of main trolley-conductors for the said collectors, and a branch conductor for each main conductor; the position of the collectors relative one to the other longitudinally of the main conductors varying with the angularity of the vehicle relative to the main conductors; a trolley frog at the junction of each main and branch conductor, each frog having a movable element'operable either to one or to the other of two positions for guiding a collector either along the corresponding main conductor or from the said main conductor onto the corresponding branch conductor; an actuating mechanism for one of the said movable elements including two electromagnets operably associated therewith for moving the said one element either to one or to the other of its operable positions; means operably associated with the said mechanism, and with the other of said movable elements, for correspondingly moving the said other movable element to its corresponding operable positions; a contact device located adjacent each main conductor in a predetermined position relative one to the other longitudinally of the main conductors and in advance of the frogs, the said contact devices adapted to be actuated selectively by the collectors as determined by the angularity of the vehicle relative to the main conductors as the collectors pass the said devices; a relay having selector switches operably associated with the said electromagnets for selectively directing operating current to one or the other of said electromagnets, and having an operating coil operably associated with one of the said contact devices for operating the selector switches in response to an actuation of the said one contact device; means operably associated with the said selector switches, and operating in response to an actuation of the other of said contact devices, for establishing a flow of operating current to the said electromagnets in accordance with the selective operation of the said selector switches; and means operably associated with the said relay, and operating in response to the actuation of the said other contact device, for retaining the selection of the selector switches as long as operating current flows to the said electromagnets.

11; In a switching system for a pair of current collectors mounted upon a dirigible vehicle; a source of power; a pair of main trolley-conductors for the said collectors, and a branch conductor for each main conductor; the position of the said collectors relative one to the other longitudinally of the main conductors varying with the angularity of the vehicle relative to the main conductors; a trolley frog at the junction of each main and branch conductor, each frog having a movable element for guiding a collector either along the corresponding main conductor or from the said main conductor onto the corresponding branch conductor; an actuating mechanism for one of the said movable elements including two electromagnets operably associated therewith for moving the said one element either to one or to the other of its operable ositions; means operably associated with the said mechanism, and with the other of said movable elements, for correspondingly moving the said other element to its corresponding operable positions; a contact device located adjacent each main conductor in a predetermined position relative one to the other longitudinally of the main conductors and in advance of the said frogs, the said positioning of the devices being such that one of said devices is actuated by the corresponding collector before the other of said devices is actuated by its corresponding collector, when the vehicle moves substantially in the direction of the main conductors as the collectors pass the said devices, and such that the said other device is actuated before the one device, when the vehicle moves at an angle to the main conductors and substantially in the direction of the branch conductors as the collectors pass the said devices; a selector relay having an operating coil electrically connected to the said one contact device and adapted to operate in response to an actuation of the said one contact device; a control relay having an operating coil electrically connected to the said other contact device and adapted. to operate in response to an actuation of the said other contact device; an operating circuit for the electromagnet adapted to move the said elements to guide the collectors along the main conductors including the source of power, a normally-open contact of the control relay and a normally-open contact of the selector relay; and an operating circuit for the electromagnet adapted to move the said elements to guide the collectors from the main conductors onto the branch conductors including the source of power, a normally-open contact of the control relay and a normally closed contact of the selector relay.

EVERETT 0. BROWN. 

